1. Field of the Invention
This invention relates to a chemically defined media supplemented with organic acids that support in vitro growth of Campylobacter and Arcobacter bacteria and to methods for using the media to culture microorganisms of the genera Campylobacter and Arcobacter. 
2. Description of the Related Art
Industrial scale culture of Campylobacter and Arcobacter is important for the production of relevant amounts of the same microorganisms and for products produced by these microorganisms during fermentation.
Campylobacter species have been recognized as important causative agents of foodborne illness. There is a strong association of foods of animal origin in the transmission of disease to humans. Contaminated water, milk, poultry, and red meats have been identified as vectors of the enteropathogen (Hanninen, Acta Vet. Scand., Volume 23, 88-98, 1982; Ooserom et al., J. Food Prot., Volume 46, 339-344, 1983). Other reservoirs of Campylobacter include asymptomatic human carriers, pets such as cats and dogs, and rodents. Campylobacter jejuni, Campylobacter coli and Campylobacter lari are known to cause an estimated 2.2 million cases of foodborne gastroenteritis per year in the United States alone (Tauxe et al., American J. Public Health, Volume 77, 1219-1221, 1987). The vast majority of these cases are associated with the consumption of improperly prepared or handled foods. C. jejuni and C. coli are the 2 major species of the genus and are responsible for about 95% of human cases of campylobacteriosis. C. jejuni is the most notable species and over 60 different serotypes of this bacterium have been identified (Franco, J. Food Prot., Volume 51, 145-153, 1988). Although the origin of this disease in humans is primarily linked to poultry, the food microbiology and poultry communities have been slow in directing substantive attention toward formulating defined media that support the growth of the bacteria. This has been due, in part, to the unique physiological requirements of these organisms, which require specialized equipment and conditions for their isolation and culture from foods and clinical specimens. Campylobacter require special microaerobic atmospheres and nutritionally rich media for growth (Kiggin et al, J. Bacteriology, Volume 72, 397-400, 1956.)
Campylobacter and Arcobacter belong to the bacterial family Campylobacteriaceae. All Campylobacteriaceae exhibit similar phenotypic characteristics and they are fastidious with exacting nutritional requirements (Park, Int. Food Microbiol., Volume 74, 177-188, 2002). The bacteria do not metabolize carbohydrates but they may obtain energy by oxidizing amino acids and intermediates of the tricarboxylic acid cycle (TCA) (Stern and Line, Campylobacter, In Lund et al. (eds), The Microbiological Safety and Quality of Food, Aspen Publishers, Gaithersburg, Md., Volume II, 1040-1056, 2000). Although Campylobacteriaceae can grow on non-supplemented media that is currently available, their growth is enhanced by the addition of supplements to these media. Existing media for the culture of Campylobacter and Arcobacter species are often supplemented with undefined components such as blood, serum red cells, etc. which do not allow for exact conditions in experimental and production fermentation. Defibrinated or lysed blood is a common supplement used in Campylobacter media; however blood-free media are desirable because of the cost and variability of the quality of animal blood used to supplement the media (Bolton et al., J. of Clin. Microbiol., Volume 19, 169-171, 1984). Many of the media used to culture Campylobacteriaceae also contain oxygen scavengers such as, charcoal, ferrous sulphate, sodium metabisulphite, sodium pyruvate, or hemin that protect bacteria from the toxic effects of oxygen derivatives (Corry et al., Int. J. Food Microbiol., Volume 26, 43-76, 1995; George et al., J. Clin. Microbiol., Volume 8, 36-41, 1978; Line, J. Food Prot., Volume 64, 1711-1715, 2001). These supplements may be used in various combinations with or without blood.
Therefore, there is a need in the art for a chemically defined, blood-free media that supports the growth of Campylobacter and Arcobacter and allows for the maintenance of these bacterial cultures. The present invention, described below, is to improved media that is chemically defined, blood-free, and different from related art media.